Wales centre Jamie Roberts is determined to end a 'rollercoaster' of a year with victory over Australia at the Millennium Stadium on Saturday.

Roberts has endured a turbulent few months including Six Nations Grand Slam glory and a serious knee injury while speculation regarding his domestic future - he is reportedly set for a big-money move to Top 14 giants Racing Metro - has been a near-constant companion.

"It is a complete rollercoaster," Roberts said ahead of his side's showdown with the Wallabies. "I remember being 18-19 years old at the (Cardiff) Blues and Martyn Williams (former Wales flanker) saying to me what a rollercoaster of emotions rugby is. And that hasn't rung more true than this year, really. You go from a high to a low, and in professional sport it's pretty brutal. But it is so important we keep working hard as a team and keep smiling. It's important we continue the upward curve from our second half performance against New Zealand last weekend.

Defeats at the hands of Argentina, Samoa and New Zealand have seen Wales' world ranking plummet and as a result they are in danger of dropping out of the top eight should they lose again in their final outing of the year. That would ensure a nightmare pool draw for the 2015 Rugby World Cup that will see them grouped with two of the world's leading sides but Roberts is not looking too far ahead.

"We've had a kick up the backside already in terms of knowing what we need to do in the Six Nations later this season," he said. "The boys are well aware of that, but we are not looking beyond Saturday at the moment. First and foremost we want to finish the autumn on a high, and there are no people more determined to do that than the players."

Roberts has been in the wars again more recently with a concussion forcing him out of the game with the Pumas and a hip injury limiting his contribution to the All Blacks clash to less than 20 minutes. But he will be back in the thick of the action this weekend and is aware of what is expected of him and the side in general.

"Our second half performance against New Zealand was where we want to be," he said. "We need to harness the energy of that and reproduce it for 80 minutes this weekend. This team has been through a tough time this autumn. Last week was obviously tough again, but the second half performance was an upward curve in a big way.

"We want to beat these guys on the weekend, and anything less than that would be massively disappointing. We know the level we need to play at. It all comes from crossing that gain-line with your big ball carriers and we did that in the second half last week. We didn't do it in the first two games against Argentina and Samoa."